The spatio-temporal characteristics of the lip-rounding parameter in the bisyllabic sequences /tiCu/, /tiCCu/ and /tiCCCu/ are presented and discussed. The lip movement analysis was done with ELITE, a device for the tridimensional automatic processing of visible articulatory movements. The results of the analysis showed that the subjects differ from each other significantly. Moreover, the durations of the rounding movement differ, depending on the type and number of intervocalic consonants, while the rounding movement appears to be independent of the presence of a syllabic boundary The data seem to be in agreement with a 'look-ahead' rather than a 'time-locked' theory.